1. Field of the Invention
The invention relates in general to a new cholinergic antagonist patch, and more particularly to a new dermal penetration enhancer for cholinergic antagonist patch.
2. Description of the Related Art
Scopolamine is one of several folksy cholinergic antagonists which selectively block the muscarinic receptors of the parasympathetic nerves in the autonomic nervous system. These medicines inhibit all actions of the parasympathetic nerves, and block some of the cholinergic sympathetic neurons, like the sweat gland nerves. However, they have no effect on other autonomic nervous neurons. The cholinergic antagonist is empirically applied as an anti-motion sickness drug, cycoplegics drug and is used with anesthetics in birth. They are also used to remedy some neurologic diseases.
Scopolamine is administered by a patch affixed to the postauricular skin for transdermal absorption. It is absorbed by the skin and transmitted to targets. Since the dermal horny layer is an ordered array of steato-dissoluble protecting films, it stops both dispersion of mist and penetration of foreign materials. General drugs have difficulty entering the body fluid through the horny layer barrier. Resistance to drug penetration varies with racial skin type. A dermal penetration enhancer circumvents the racial differences and serves to carry the medicine into the body's fluids.
The penetration enhancer may be a surfactant of some sort. This compound is usually used as a component of various paints to help the carry of the main component, or as a emulsion for the cosmetic maintenance of skin. The surfactant usually has one lipophilic long carbonous chain terminal group and one hydrophilic hydroxyl or amine terminal group. These terminal groups bond with the main component as a carrier. The composition always plays an important part in the medicine design.
The choice of an appropriate surfactant is important since dermal penetration ability of surfactant varies, depending on the drug bound to it. In order to choose an appropriate penetration enhancer, the present invention uses different surfactants with scopolamine to compare dermal penetration abilities. In addition, this invention compares concentration intergrade in dermal penetration to discover the nature of the penetration ability.